One advanced option which should be available on today's cars is external cameras. I don't mean so that the driver can see in extra directions; drivers shouldn't be encouraged to be looking down at the screen anyway, and HUD's aren't really practical yet for most buyers' budgets. I'm thinking of digital cameras that are mounted to see more or less what the driver can see. They're configured to record at all times, each writing to a rolling buffer of about five minutes or so. If you hit the "SAVE" button, it dumps the buffers to disk.
Why is this useful? Let's say you're proceeding (with a green light) through an intersection. Some guy comes barreling down the side street, driving straight through the red light and cutting you off. You swerve and slam on the brakes, narrowly avoiding hitting his car, or perhaps almost but not quite slamming into a lamppost or even another vehicle. Or maybe just getting really ticked off. He gives you the finger, or maybe he just laughs at you and goes on his merry way. He's probably done this before, and he'll probably do it again (and next time, the other drivers might not be so lucky as you), but since no collision occurred, what can you do about it? If you report it to the police, it's just your word against his, and it's unlikely that you'll have caught his license plate number in time anyway.
Unless you just happen to have recorded the whole thing...